High speed printer



f8, 1959 lwJAcoBY HIGH SPEED PRINTER 11 Sheets-Sheet 1 Filed June 13,1955 INVENTOR.

MARVIN -,uncovr du 5f was. upm Zw 2 H PCSU 'Dee s, 1959 Filed June 13,1955 11 Sheets-Sheet 2 cHARAcTER TRANsFERRED II11ob u f FIg. 2o f2 SP1vDIF y lIosa ,101' DE 29.9 108 PRINT ,u PULSE o-.DIF "s Esog \|oe PREVENTPRINT b PxuLsE -DIF READINC G FROM He sP SP1 SP2 M14 f f110D m4n DELAYLINE I v Q INPUT G21 Y DIF 105 FLIP-FLoPs sl Y 1Ds I DELAY s IDIJ I A Rn E i 100 Y l I l Ol. l |111 I OB l I I4 I TAPE I :To: l I II I I l 1 Il i G2!! v IoA I i I I l |A\ s I 10c I I/ I I R m J CLUTCH I4 BRAKE I 49Non PRINTms INVENTOR 11 sPEclAL sYMBoLs "RW" J^Y FROM FLIP-FLoP DECODERa cIRculT I5 FIGA uf A ENT Dec. 8, 1959 l M. JAcoBY 2,915,966

HIGH SPEED PRINTER Filed June 13, 1955 11 sheets-sheet s START @E11 SEEF i g- 2 b CLEAR T I l 110/ sTEP/ m @E lig ac Bc Bc Bc L M. JAcoBY HIGHsPEED PRINTER FRDM mpuT FLIP-FLoPs NONPRINTING l SPECIAL sYMBoLs DECODER1B JACKS 6 START Filed June 13. 1955 FROM FIG. 2b

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HIGH sPEED PRINTER Filed June 13. 1955 11 sheets-sheet e CHANNEL FASTFEED Y d INVENTOR.

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. 8, 1959 M. JAcoBY HIGH SPEED PRINTER 11 Sheets-Sheet l1 Filed June l5,1955 United States Patent O HIGH SPEED PRINTER Marvin Jacoby,Norristown, Pa., assignor to Sperry Rand Corporation, Philadelphia, Pa.,a corporation of Dela- Ware Application June 13, 1955, Serial No.514,852

33 Claims. (Cl. lill- 93) As will be brought out more fully hereinafter,the

present invention utilizes a continuously rotating typewheel, orcylinder, which contains a plurality of identical, peripheral rows oftype characters arranged so-that the corresponding characters in eachsuccessive row of type are (generally speaking) essentially axiallyaligned over the length of the wheel. The intelligence to be printed isrepresented by a binary coded signal, such as that obtained from variouselectronic computers, which is stored in an electronic memory circuit.This storage is done in such a manner that each alphabetic, numeric, orother special character to be printed in one or sometimes more completelines of type is stored at a different location in the memory circuit.Each of these memory locations controls the actuation of a print hammerassociated with a diiferent row of type on the wheel. Ganged to thetypewheel and operated synchronously therewith is a code generator whichgenerates a binary code representative of the particular type characterinstantaneously under the print hammers. The code generated by the codegenerator is compared with the code stored in the several locations ofthe memory circuit. When the code generated by the generator correspondswith that stored in any one or more of the several memory locations, theprint hammers under control of these locations are actuated and thecharacters to which this code corresponds are caused to be imprinted onthe paper. After one complete revolution of the typewheel, one completehorizontal line is printed, and the memory must be cleared and refilledwith new information for the next horizontal line.

It is an object of this invention to provide a novel, fully automatichigh speed printer.

It is another object of this invention to provide a high speed printerwhich is capable of producing many varied printing formats.

It is another object of this invention to provide an electronicallycontrolled printer for converting coded information stored on magnetictape or the like into printed fonn.

It is another object of this invention to p-rovide a high speed printerof the foregoing class wherein the printing paper is advanced during theinterval that coded information is being fed into the memory circuit.

It is another object of the present invention to provide a novel highspeed printer of the foregoing class wherein the printing paper may befast fed to predetermined locations during the interval that codedinformation is being fed into the memory circuit. v

Another object of this invention is to provide a fully automatic highspeed printer of the foregoing class which 2,915,966 Patented Dec. 8,1959 ICC is particularly adapted to be used with electronic computersutilizing binary coded signals.

Other objects and'features of thepresent invention will become apparentupon a careful consideration of the following detailed description whentaken togethe with the accompanying drawings, in which i v' Figure l isa simplified block diagram showing in generalized manner theorganizational layout of the present invention, Y Y

Figures 2a and 2b show in block diagram form the circuits for lling thememory system with coded information,

Figure 3 shows in diagrammatic form the circuits used to suppress fromthe memory system certain predetermined codes which it is desired not toprint,

Figure .4 is a block diagram illustrating in greater detail the magnetictape control circuits employed by the instant invention, r

yFigures 5a and 5b show in detailed block diagram form the printingpaper control circuits utilized by the present invention, Y

Figure 6 is a simplified schematic drawing, partlyin block, showing thecircuits used to alter the interconnections between the various memorylocations inthe memory system and the printfhammers included in theprinter, Figure 7 is a block diagram of circuit components used tocontrol the printing circuits shown in Figure 9,'

Figure 8 is a block diagram illustrating one possible type of codegenerator useable by the present invention, `and Figure 9 shows inschematic formfthe print actuating circuits of the printer. In thedrawings and in the description to follow, the use of the term delay Hopor the abbreviation DF will be taken to mean a one-shot multivibratorwhich has one condition of stability and two outputs. The iirst output,when used, which by the convention used in the drawings will be showncoming from a line directly opposite the input terminal, will beundelayed and will persist for a period equal to the period ofinstability of the circuit when it has been triggered. The secondoutput, when used, will be shown in the drawings as coming from a linedisplaced from the input line and will represent the delayed outputgenerated coincdentalwith the return of the circuit to its stablecondition following the receipt of a triggering input. Also in thedrawings, flip-flop circuits will be labeled by the abbreviation Fl-1,buffers by the abbreviation B, and gates by the abbreviation G. In thecase of gates, the input terminals designated by a small circle willindicate an inhibition terminal, while the non-circled input terminalswill indidicate permission terminals. Signal pulses applied to thecircled terminals, of course, will block the gate, while signals appliedto the non-circled terminals will open the gate. Wherever possible,similar reference characters .have been used to indicate correspondingelements throughout the several figures comprising the drawings. k

In a generalized sense, the organizational layoutcomprising the instantinvention may be represented by the simplified block diagram shown inFigure l, to which reference is now made. As aforementioned, the signalsfrom which the printer derives its information `exist in the form ofbinary code combinations. Although this invention is not limitedthereto, one convenient manner for obtaining these signals is from amagnetiz'ed tape record. In a typical example, the tape carrying the'represented by a magnetic spot recorded in an approprima charm-e1forirfheaape, while die binary digit o'f 'For reasons ofsimplicationthis .channelwill-be-'dis- :regarded n the' rvdiscussionthat 'ensues.- yA-fseverith chaninel'referredftdas aspro'ck'et pulseYchannel has `a mag- @neftized spotk occurring at each -point along thetape where the other 'six :informationV channels comprising i`safset'of'binarysignalslare to be recorded. For con- -venience,the'information recorded on`the tapeappears www ingblockette form whichcomprises a record of 120 sets of` binary `.signals disposed along thetape.

To reproduce lthe information recorded onthe' tape a suitable tapereproduction device, such as generally indicat'ed a't 10, is"` employed.'This reproduction'system #includes a multichannelhead structure 10a,which includes a separate'head -for eachof the channels recorded *l lYon the-tape;'-a supply reel'10b and a take-up "reel 10c.

l"l'he'jtape' is lpa'ss'ed over vthe multichannel *head 10a from thesupply reel 10b to the take-up reel k10c at'allunilfomrate oflspeed'bya'motor 11. :Themo'torjIl includes ashaft l2,"which Ais coupled to theta'pe transport mechanism 10Y throughva suitableclu'tch 13 andibrakefmechanism `14. In practice, the clutch 13 and .#'tha't lafsigna'lcoming `in .on its set input terminal S,

such-*as vby closure of start switch k17, 'energizes the y'and causesthetape'transport mechanism to draw'the tapeacross t-he head from"supply reel 10b to .the ytake-up reel 10c. To stop this action, asignal on fline 18 arrivingat restore input R of the iiip-op circuit 154reverses the bistable device 15 to `deenergize clutch 13 "and energizebrake 14, which stops further rotation of the tape transport mechanism.

As the tape Vpassesoverfthe multi-channel head 10a, fthe binary )signalsrecorded on -the magnetic tape vinducejplsating voltages intherespective pick-up head, .Whichvoltages are' applied throughcorrespondingleads Y@to a'gr'oup-of vpulse shapers indicated generallylat 19. -Ij practice and .for reasons Which will appear more fullyhereinafter, these 'pulse Shapers may typically. comprise hip-Hopcircuits 'which are operated toone condition ofI stability. by Vthechannel information pulses recorded pn'theQtpe-and are periodicallyrestoredto kthe `other condition of 'stability by a delayed sprocketpulse. The information 'thus l.derived-from Vthe tape by 4the `pulseShapers l1`9 and multi-channel head 10a is `appliedthro'ughanf'add'ressline selector 20 to a memory circuitr 21. The-memorycircuit, which may be a gas `tube type of 'memory' such as disclosed .inthe- Eckert and rMasterson application supra, will include as vrnanydistinct memorylocations as Ythere are Ysets of binarysignals :in theblackette, which in ythis ,case is v120. Each of these ebrakeftlI/may beelectromechanically Operated from a *v memory circuit 21.

memory locations includes a separate gas tube for each ofthe.six.information.channels-recorded on the tape. "In

p'ractice where the odd-even-check pulse 'channel-is'used, seven gastubes. are employed-at *reach -memory vlocation, but as 'mentionedhereinabove only six information channels will Ybe=considered. Theaddress' line y'se- "lectorf20,k which foperatesl in general Vas adistributor,

functions to take -eachisuccessive set of binary signals recorded on thetape andfto`apply-these^sets to successive positionsg-in'the memory. Theaddress line selector may be -.o`f `any convenient design. For example,`a

set -of lbinary counters having at 'least 120 states and 'set of binarydigits uis/appled Ato the rst memory loca- ..tion,..the,second .set to.the second 4memory location, Aand `it also sends a permissor signalback through line 21a to gate circuit-22. A`In response tothe -combinedeliect .of the permissive signall from control circuit 15, and a secondpermissive signal (end of paper-feed signal generated by paper brakesignal source 45 as later described), gate circuit 22 does two things;'it sends a signal back -through "dilerentia'tor `60 to the reset input61 of the address line selector 20 `to 'clearthe counter in this unitv(the `counter :here .is also initially cleared bysWitch contact l'whenithejsprinter is'iirst .-started),. and it transmits -Vanother Signal tocode generator 23. This :latterf signal functions to permit the outputof the code generator `totappear at.the several output terminals cou--pled 'to' this device. As indicated, code generator 23'includesfanelement which is ganged to the shaft 24y of 'the print Wheel25 and is .rotated synchronously with the print wheel ibymotor 26. Codegenerator 23, gen- ;erates afchangingy binary code, the instantaneouscode combination of Whichzis representative of the type charactercontained on the print wheel -25 that is instantaneously-under the`print hammer head 2'7. This chang- 'ing binary `code is vappliedthrough a set of output .lines `Zto a comparator y29, wherein the vcodedinformation jstored .in the memory'is compared with that generated 'by.code generator.23. This comparison is effected lin .'sucha 'manner.that as the code generator delivers a binary signal representative, forexample, of the character A, all 'the As recorded in the memory circuit21 'arecompared simultaneously. fIn practice, thereis One comparatorcircuit .forfeach memory location in the These-comparators control theactuation. .of theA individual print hammers located in the printinghead 27 through lthe operation ofthe printing `circuits`f30. Alsocoupledto'thefprinting circuits vlili is a .print :control '.'signal kfed -inon line 31 from the code generator .234 This signal appears in the formof a 'seriesof pulses, twopulses for each new codecombnation" generatedby the code generator 23. To digress momentarily,it `will be` seen byvreference to the Eckert and 'Masterson application supra, that eachperipheral type'row contains a total-of-51'-diierent characters, withthe identical characters in successive peripheral rows beingangularlystaggercd .in an alternating manner. In more particular,identical type characters in the odd numbered iperipheral rows4 lie1in-foneY common longitudinalplanewhilethose in the 'even numberedperipheral rows lie in a second plane half-way angularly .displaced fromtheplaneo'f'the'odd 'numbered peripheral ,.rows. Thus, although-fthe.code igenerator need only generate 51 different code fcombinations, twoslightly Ytime displaced printing pulses must be generated for each codecombination in lorder to takelinto account the diierence in time-of.arrival .of the odd 'and-evennumbered peripheral type rows xunderrtheAprint hammers. The print control signals :derivedifrom theoutput of:the Code generatorare also fedv back .through a line 32 to the stepinput of the. address lineselector. This connectionadvances the counterin theaddresslineselector two steps for each ot the dierentcodecombinations whichthe generator'23 generates (a total Aof `l02 steps).kAftenthe generatonhas produced all the different code-combinationswhich are printable fby fthe typewheel 25, the-couuterin address lineselector 20 attains a predetermined count (102) and sends a signal backthrough line 33 to the code generator 23. In response to this signal,the code generator 23 stops delivering signals on its output lines 31,28 and 32 but delivers a momentary signal on its output line 34 whichdoes a number of things. The signal on the line 34 is applied to thememory circuit 21 as a clear signal to clear the memory circuit; it isalso applied to input 61 of the address line selector circuits 20 toclear this circuit; and it is `further applied as a read start signalthrough now closed switch contacts 17 to the ip-op control circuit 15 toenergize clutch 13 and deenergize brake 14. This permits the nextblockette of information recorded on the tape to be read into thememory. At the same time that control circuit 15 removes the brake 14energization, the signal on line 21a which was applied to gate 22 isremoved. The removal of the signal on line 21a operating through gatecircuit 22 functions to suppress further outputs from the code generator23 until the next printing cycle is inaugurated.

The momentary signal on the output line 34 of the code generator 23,which as above described starts a new read-in cycle for the memory, isalso applied through line 35 to a paper feed control circuit 36 so as toinitiate print paper movement during the read-in cycle in a manner nowto be described. Circuit 36, like circuit 15, is a bistable switchwhich, when energized from the input from line 35, operates to energizea clutch 37 and deenergize a brake 38. As clutch 37 is energized, themotion imparted to shaft 39 by the motor 40 is translated to a paperadvance sprocket 41, which starts to feed the print paper 70 through themachine. For purposes of simplification, the ribbon and ribbon feedmechanism usually associated with the printing paper and hammers havebeen deleted from the drawing since any conventional ribbon controlmechanism may be used if desired. Aixed to the paper advance wheel is anoptical flat 42, on which a source of light 43 is focused. As the paperis advanced and the optical at 42 rotated, the light from source 43 isreflected by the optical flat 42 to a photocell 44. This occurs when thepaper has been advanced a suitable space or number of spaces. Thephotocell 44 operating through a paper feed brake signal source 45 isactuated to deliver a control signal through a gate 46 to the paper feedcontrol circuit 36. This signal restores the paper feed control circuit36, energizing brake 38 and deenergizing clutch 37 to stop furtherrotation of the paper advance wheel 41. To insure that the next printcycle does not occur until after the paper feed has stopped, the paperfeed brake signal source 45 also delivers a control signal to thecontrol circuit 22. The signal from source 45 together with the signalfrom flipop 15 occurring on line 21a at the end of a read-in cycleprovide the two permissor signals for gate 22 as above described.

Since a six position code is used and only 51 characters are carried bythe print Wheel 25, it is apparent that the number of code combinationswhich can be fabricated using a six position code is greater than thenumber of printable characters. The excess of these code combinationscan be utilized to initiate certain command signals for the machine.These command signals, which appear as binary code combinations recordedon the magnetic tape and distinguishable from those code combinationswhich represent print characters on the print wheel, can be derived fromthe pulse Shapers 19 by a conventional decoding matrix network 49, forexample, and fed to other control equipments in the machine. Forexample, one or more of the command code combinations could be used toyproduce a fast feed operation for the paper drive. These controlsignals usually occur, ifat all, as the first character in a blocketteof information on the tape, and when reproduced by the head a produce anoutput from the matrix 49.

In the event of a fast feed symbol, matrix 49 produces a pulse output at62, for example, which is fed to a fast feed stop signal source 50 andto the set input of flip-flop 63. The latter connection to the flip-flop63 operates in response to the receipt of a fast feed signal from matrix49 to block the gate 46 and thus prevent the paper brake signal source45 from shutting off the paper feed circuit 36. The fast feed stopsignal source 5t), on the other hand, operates upon receipt of a fastfeed command signal to replace the normal action of the paper brakesignal source 45. To stop paper feed under these conditions, a s eparatepaper feed program loop 51 is utilized. This loop may be a continuouspaper belt which includes a series of perforations located thereon anddriven from the paper advance wheel so ythat the perforations bear acertain relationship to the position of the paper under the print head27. Hence, under the command of the fast feed signal derived from matrix49, gate 46 is inhibited by the flip-flop 63 and the paper brake signalderived from source 45 is blocked from paper feed control circuit 36 bygate 46. Paper advance wheel 41 then continues to rotate, driving theprogram loop 51 until one of the holes in this tape registers with acorresponding one of the contacts 52 of the fast feed stop signal source50. At this point, the fast feed signal source 50 delivers a restoreoutput signal to the flip-flop 63 which removes the inhibit from gate 46to permit the normal stopping of paper Via the paper brake signal source45, the gate 46, and the paper feed control circuits 36.

With the foregoing generalized picture of the printing machine in mind,the details of the manner in which the coded information is fed into thememory circuits and the operation of the pulse Shapers will now bediscussed in connection with Figs. 2a and 2b to which reference is nowmade.

As indicated above, each character to be printed has been previouslyrecorded in coded form on some recording means as, for example, onmagnetic tape. The input circuits of the machine transfer thesecharacters from the tape to the memory. The input section of the machinecomprises also driving means for moving the recording medium across areading head. Both these driving means for the recording medium and theinput circuits are illustrated in Figure 2a.

Figure 2a shows on its left hand side the magnetic head 10a and a supplyreel 10b from which the magnetic tape is moved across the magnetic headto the take-up reel 10c. This motion is accomplished with the help of amotor 11 and is controlled by a clutch 13 and brake mechanism 14, asdescribed herein above. The clutch and the brake, in turn, arecontrolled by signals from the lflip-flop circuit 15 and the signalsderived therefrom will be explained hereinafter in connection with Fig.4.

If the recording was done on a magnetic tape, as is assumed herein forthe purposes of illustration, a character may appear on that tape as arow of small magnetized spots. When the tape carrying such rows of smallmagnetized spots is moved across the magnetic head, these spots areconverted into electric impulses. It is assumed, for purposes ofillustration, that the number of magnetic channels on the tape is seven.In such case, one of the seven channels, preferably one of the centerchannels, carries a sprocket channel pulse which is a timing pulse anddoes not bear any intelligence. The other six channels, in contrastthereto, are provided for the selective representation of the digit codecombinations. The pulses emanating from these six channels shall becalled information pulses or information signals so that they may bedistinguished from the sprocket channel pulses.

Characters may arrive at the magnetic head approximately every eightymicroseconds.` This means that -.:eve1zy-,.eighty microseconds onesprocket channel pulse .is received. vThe-.magnetichead 'which is anelectromag- L'netic .transducer transforms this sprocket channel .pulseintoanelectric impulse which is amplified in a `conventional :amplifier100. The amplied sprocket channel vpulse -maywbeuslightly delayedrelative tothe simultaneouslyarriving information pulses occurring .inthe six .information channels, as by .applying the sprocket pulse .totla conventional .delay element 101. The delayed sprocketchannel pulse isthen shaped by a squarer 102 and differentiated V by diiferentiator 103.The differentiated.signalisreferred to in the specification and drawingsas .sprocket pulses SP appearing on line 104.

The machineyuses-three signals which are derived from the originalsprocket channel pulse SP. These three `signals are the sprocket pulseSP, as described, Vand successively delayed :sprocket pulses SP1 andSP2. The -latter pulses lare-produced by means of any suitable 'knowndelaying device 105 coupled to the line 104. The .respective `delays maybe, preferably, so arranged VAthat the sprocket pulse SP1 occurs abouttive microseconds after the sprocket pulseSP, and that the sprocketpulse W.SP2 occurs about two and one-half microseconds afterthesprocketpulse SP1 or seven and one-half microseconds after the sprocket pulseSP. The purpose of using three sprocket pulse signals and the describedtime relationship-will become apparent hereinafter when thelalllp'lication of. these signals is discussed.

Turning back now to the magnetic head a and to Vthe assumption that thetape carries six information channels, lthe electromagnetic transducer10a transforms the magnetic information signals into essentiallysimultaneous electric information signals. It ought to be stressed, in`this connection, that it depends entirely upon the selectively appliedbinary code combination which ones of the channels carry a signal(binary l) and which ones ofthe channels are, at a given time, Without asignal '(,binary"0). For the purpose of illustration, it isfurtherassumed that the code combinations are arranged aslindicated inthe binary system. This means that the 'code combination consistsexclusively in selective combinations .of Os and ls because there are noother iigures available in the binary system. The presence of a signalmay 'then be interpreted as a 1, and the ab- `sence ofthe signal may beinterpreted as a 0, or vice versa.

`:Each electric information signal appearing in a respective channel onthe tape and emanating from the corresponding `electromagnetic pick-upin transducer 10a is ampliiied in a corresponding amplifier A andtransmitted tothe set vvinputs S of respective input flip-flops I to VI.Thesellip-ops, and Vall flip-flops hereinafter referred to, may beconventional bi-stable devices which are set to one conditionofstability.in response to the occurrence 'of'signals on their set input terminalsS and restored to f a secondV condition of stability in response tosignals applied to their restored inputs R. Under the assumption-that'the tape carries six information channels, the machine provides sixinput flip-ilops l to VI inclusive, eacfhrof'which corresponds to one ofthe six information channels on the tape. For the purpose ofsimplication, only the input flip-ops I, II and VI have been shown.Itrfollows from the application of binary code combinations that, inevery individual combination, some of these input flip-flops kreceive asignal from the transducer while other do not receive such signals. Theflipops which receive a signal are set, in contrast to the fiipdiopsywhich do not receive a signal and which, therefore, remain .in theirrestore state. The input flip-flops which areise't transmit a signal torespective input gates G2 l toGZ-VIinclusive, ofwhich only G2 I, G2 lland G2 VI are'fshownfThe signal from an input flip-flop to itsassociated input gate conditions such gate for passageof-ranothergsijgnal.*whichifgoes into thememory. This other signal isthesprocket .pulse SP1 derived from-delay line-.105, 'and applied inlparallel to thef'gates' G2 I to G2 VVIv in the 'manner `hereinafterdescribed. It now becomes evident :why the` pulse SP1 .occurs aboutvtive microseconds afterV the jpulse rSP, as --described :hereinabove.The pulseSPl Vis.tobecomeeffective at a-time when `the input gates arealreadyv selectively` conditioned for the passage of SP1. This explainsalso why flip-flops are provided for the emission of the conditioningsignals to the input `gates becausethisway theinputgatestare kept openfor thepassage of SP1 as long as theirrespective input ilip-ops remainin the set state.

Figure 2a shows, in its top section, a 'conventional delay op (DF) 106.When triggered, delay-flop 106,pr0- duces a separate output atleach oftwo output 'terminals '-107 and'108. The output occurring at terminal-:10S-occurs instantaneously with `the triggering'of the "circuit andlasts vfor 29.9 microseconds, while-the output -at the yterminal 107occurs delayedfrom the instant triggeringby 29.9 microseconds. [There`.are three different signals which may go into the input of the delayflop 106 to trigger this circuit. The pulse SP1, is the only-onezamongthese three dii'erent'signalswhich :appears during, afreadin cycle, thatis, duringthe-time that informationis being transferred from the tape tothe memory -circuit.` The other two signals, :called print a pulseandrprint b pulse, originate in the code generator of Figure 8,V andwill be described later. These last mentioned :signals appearexclusively during the print cycle of the machine and have noconnection, therefore, to the transmission of information signals intothe memory. As indicated in-the drawing, it is the undelayed-outputof-delayop y106V appearing at output terminal -108 which travels throughthe input gates, G2 I'through G2 VI, via gate 114 provided that theinput lgates are conditioned for passage of a signal from theirassociated input flip-flopsl through VI. After passing the input gates,the sprockety signals SP1 `as shaped by delay ilop 106 enter the memoryofthe machine where they -are appliedto the grids of specific memorythyratrons, as will be explained hereinafter.

After 29.9 microseconds, delay flop 106 restores. vThis means that 29.9microseconds :is regarded as the maximum time available for the transferof information into the memory. The differentiated restore outputproduced by diierentiator 109 .is used for three purposes, as indicatedin the drawing. First, Vthe differentiated restore output of thedierentiator y106 .is fed back through line l10n to the restoreterminals of the input flip-Hops to restore these circuits; second, thesame output appearing on line 110b is used as a signalthatfcharactershave been transferred into the memory, which signal is the restoresignal for the prevent read-in flip-flop 401 in Figure3; and third, thisrestore output steps the address-line sevenstage binary counter 111through line 4110e as shown in Figure 2b.

It has been stated hereinabove that the print a pulse and the print bpulse also applied to therdelay-flop -106 appear exclusively during ytheprint cycle of the machine, as will later be described. During the printcycle, the tape from which the memory is filled is stopped andconsequently there is neither a need for restorin'gthe input Hip-flopsnor a need for restoring the prevent read-in ip-flop 403i. Therefore,the only purpose of using (.set) signals vfor delay .ilop 106 is toObtain the third effect mentioned above, namely to step the seven-stagebinary counter E11. This counter counts during the print cycle the stepsinvolved in the printing operation for reasons which will be explainedhereinafter.

The memory 21 in Figure 2b comprises, in the given example, 720thyratronswhich arearranged in '120 .address-lines, or memory locations,corresponding to the sets of binary signals used to comprise oneblockette of signal information stored in the magnetic tape. Each lineor memory location .labeled 0 to 119 in the drawing contains the sixtubes neededto store the six binary symbols `ofthe assumed`six-positioncode `combination. The

memory is capable, therefore, of storing 120 sets of binary characters.When a binary character from the tape is read into the memory, onespecific line of tubes must be alerted to receive it. The address-linesevenstage binary counter 111 which can count up to and including 128remembers which one of the 120 addresslines should be alerted. Since thememory has only 120 address-lines, the last eight counts of theseven-stage binary counter are not used. The binary counter is stepped120 times which corresponds to the storage of 120 characters.

In order to select the appropriate address-line, the binary counter 111outputs are applied to the addressline decoder or matrix `112 which maybe of any conventional design. 'Ihis matrix 112, which together withcounter 111 corresponds to the address line selector or distributor 20of Fig. 1, applies an enabling voltage in parallel, as shown, to thegrids of all the memory tubes in each address-line in succession.

The address-lines are numbered from to 119. Whenever the address-lineseven-stage binary counter 111 is cleared, the six thyratrons I to VI onthe 0 address-line are primed at their grids to receive the rst binarycharacter derived from the blockette of information stored on themagnetic tape.

Each successive sprocket pulse SP1, of course, steps the counter 111 oneposition and primes the next memory location in sequence. Whenever thebinary counter reads 119 the six thyratrons on the 119th address-lineare primed to receive the 120th character.

As indicated hereinabove, the binary digit l is represented by a pulseappearing on the tape while the binary digit 0 is represented by theabsence of a pulse. Thus, from the foregoing it will be seen that in thememory circuit the binary l stored on the tape and applied through theappropriate gates G2 I through G2 VI to the grids of the memorythyratrons will ignite the corresponding memory tubes to indicatestorage of the digit 1, while the binary digit 0 which is represented byan absence of a pulse leaves the corresponding memory tubes in anon-conducting condition.

For obvious reasons, the binary counter 111 is cleared to O beforeeither a reading or a printing operation. Three signals may be used toinstigate a clear in the binary counter. These are indicated in the topsection of Figure 2b. There is first the read start signal from gate 275in Figure 9 later to be described; there is further the manual startsignal which originates at the control yboard of the machine; and thereis finally the start print cycle leading edge (LE) signal whichoriginates in the print control circuits in Figure 7, and which appearsat the beginning of every print cycle.

Figure 2b shows, for reasons of simplification, only four address-lines,namely address-lines 0, 1, 102 and 119. These four lines have beenselected for specific showing because they do not only furnish thepriming signal to the grids of the associated memory tubes but theirrespective signals are also used outside of the memory section of themachine. The address-line 0 signal and the address-line 1 signal areapplied to the fast feed circuits (Figure 5b), as will be explainedhereinafter in connection with the fast feed operation. The addressline102 signal is fed to gate 240 through terminal 239 in the code generator(Figure 8) to indicate thatl 102 printing steps have been performed aslater described.

Turning back now to the operation of the thyratrons in the memory, ithas been stated already that, due to the operation of the seven-stagebinary counter 111 and of the address-line selector decoder 112, onlyone address-line is conditioned, at any given time, to store theinformation signals coming through the input gates. This conditioning isaccomplished by connecting the grids of the tubes in each memorylocation to the selected address-line output of the decoder 112 whichsupplies a voltage which, in combination with the addi- 10 tionalvoltage furnished by the signals coming through the input gates,produces the necessary bias to ignite the thyratrons.

As to the anodes of these tubes, they are normally kept at a relativelyhigh voltage as, for example, plus 213 volts by the output of anotherdelay multivibrator or the delay op DF113 causing a much lower voltageas, a printing cycle is complete, the clear memory signal coming fromthe read start line in Figure 4 triggers the delay flop DF 113 causing amuch lower voltage as, for example, plus 55 volts to be applied to theanodes of all the memory tubes for a short interval of time. Thisde-ionization process lasts for 5.5 milliseconds, as a result of theoperation of delay op 113.

Referring again to the input flip-flops shown in Fig. 2a, the outputsignals from these flip-flops do not only go to the input gates G2 I toG2 VI as explained hereinabove, but are also transmitted to thenonprinting special symbols decoder 49 shown in Figure 2a and again inFigure 3. This decoder may have the form of a conventional matrixnetwork and is identical with the matrix 49 shown in Figure l. Thedecoder 49 operates to produce output signals on predetermined ones ofits several output lines whenever predetermined codes are set up on theinput flip-flops by the codes stored on the tape. The nonprintingspecial symbols referred to in the name of the decoder have already beenbriefly explained hereinabove as command signals for the machine. Thecode combinations representing such command signals differ, of course,from all those combinations which symbolize the characters to beprinted. These signals are, therefore, not to be stored in the memorycircuit since they do not represent printable information. To give a fewexamples for command signals of this kind, the following command signaloutput lines are shown at the decoder of Figure 3: fast feed 1, fastfeed 2, stop, and multiline, each of which is represented by a separatebinary code, which is distinguishable from the printing codes and fromone another, stored at the first position in a blockette of informationon the tape.

Fast feed is one among the many features of the machine which serve tospeed up its operations. Its purpose is to move the paper in one singleoperation from the last line which was previously printed to any desireddistant line on which the next following printing is to be performed,thus eliminating any stepwise motion of the paper. Details of this willbe described in a subsequent section of this specification. The onlypoint to be discussed here is the fact that the magnetic tape may carrycommand signals to the machine for fast feed, stop, multiline, etc. andhow these command signals are blocked from the memory.

Figure 3 shows two fast feed output lines from the nonprinting specialsymbols decoder 49 which carry the label fast feed 1 and fast feed 2,respectively, one multiline, and one stop signal. This means that thereare at least two different fast feed code combinations, one stop signal,and one multiline signal which may be received from the magnetic tapeand decoded in the decoder. The resulting output signals fast feed 1 orfast feed 2, sto-p, and multiline leave the decoder 49 upon arrival ofthe correlated sprocket pulse SP1 applied to terminal 404 of decoder 49.These output signals, representing nonprintable information, are buifedby suitable buffer ampliiiers B into the set input terminal 402 of theprevent read in ip-op 401. The flip-flop 401, when set, sends aninhibitory signal to gate 114 in Figure 2a which prevents the stretchedoutput signal from delay ilop 106 from passing through this gate. As aresult, there is no signal which could pass through the input gates G2 Ithrough VI, and the present code combination is not fed into the memory,therefore. After 29.9 microseconds delay liop 106 (Fig. 2a) restores,and its restore output signal is fed back under the label of charactertransferred to the restore input terminal 403 Vof the preventresidua-starren? ma@ Fig're bina'fiens appearing o'itheftapblockettefnra'y thenfbe fedro the memory'-circuitlferfstrge.-

The deco`dei'"deeode`s not" only command' slgnalsas".

described Vso 'fanlhut'it 'decodesalso the co'de'combir'la'tion' which"represents 'a"-decimal-'zero; This isdoneforT the' p'ii'io'se"of`suppressing the printing lof zeros', ifsofdesi'red..

The arrangement andoperation of the" ze1o` suppress f circuits will be"explained' in a7 subsequent` part ofthe! specication'. The'A only pointto'be stressed'at tlnsftlr'neV isfthe fact"that,--whenever a zero'fisnot' to be printedg-va;

sprocket p ulse SP1 isi sent"thi'ough the zero suppress:

controlagate.r 406 (Fig-.- 3) tothe "set input terminali 402 of? theAprevent read" in hip-11013140110 inhibit 'gate 114-" in' Figure 2a, asdescribedhereinab'ove;

Figure' 4` shows on'its" right' hand fside Vthe tapedrive liplop 1.5,'the; operationofwhich controlsthe' clutch and brake'mechanism' of'thetap'e'A drive, asmen'tiohedf hereinaboveV in' connection withl bothFigure lf and-'FigU ure 2. Turning' now" to the cir'cuits'lwliich governthe the input" of the manual start vsignalfwhich comes from the control'board of the machineand which` occurs whenever theV machine is initiallystarted; After'the' machine'has completed its'rst read-incycle'and'subsel quently its first print cycle, an` automaticallyproducedVA signal takes 'theplace of theorigirial manual start si'gn.

This automatic signal is called `read start signal'and entersY thecircuit at theterminal ,461), shown onv thel leftV of- Fig; 4;

print'cyclehasrarrivedfata-'successful conclusionljY Thereadstart'signal, after'entering a't point 460, 1s

appliedto gate 461i4 which, during normal operations;- is always open.This gate receives aninhib'itory signal? only if and when the multilinein-pro'c'ess-fip-'flop 442 This flip-fiop`442 will 'bediscussedhereinafterI It suices-at is set. in connection with multilineoperations. thispoint, to sfatefthat the machine doesf not read 1n whilemultiline is in process. The read start signal is,

therefore, not permitted 'to pass through gatel 461fundertime of 2.5millisecondsand which produces anf output signalwhenit returns toitsrestore state'. This delay is introduced as a'necessity.` The clearingof'the memory takes about 5.5 milliseconds, and it is, therefore,desirable that the input ip-Hopsof Figure 2a do not begin "to send outsignals before thisclearing operation is" completed. An essential partof the necessary delay isl al'readyp`ro-v vided by the fact that ittakes some time to set flip-flopV it comes from gate'275 in thefprintcircuits." of Figure9, and emanates from' thatgate whenever a'V 15, toenergize the clutch mechanism y13 through the set' output of thisflip-flop 15, to bring the tapedrive up to its normal speed, and tocover the space between blockettes.` Delay ilop 463 providesthe'additional delayl` of 2.5 milliseconds to ensure that the signalsfrom the,

magnetic head 10ft of Figure 2a do not arrive too early inl the inputcircuits.V

The output-signal fromthe delay flop 463 is ythen differentiatedYV bythe diferentiator 464' and buied-by ai 70,. conventional buffer circuitB- into ythe set- -input terminaly 466 of -the tape 'drive'flip-ilop/IS;The set-output of-this flip-Hop 15'energizes th efclutch'13,sho'wn in'Figurelm andthe -tape begins to'move- Aacross the electromagnetic'transducer-.f- Thisrepresentsethebeginning-of `-therTread-inem;

, It has beehmentioned hereinabove' that'during read-in theaddress-line119 signal (Figure/2b) notor'ily primes theV- memory tubesin'addr'e'ss-line V119, but also* permits the'v restoring oft theflip-flop circuit 15 to terminate thev read-in cycle. The input of theaddress-line 119 signal into the circuits of Figure 4 is shown at theterminal 492 as aV permissive signal applied to gate 491, permitting thenext following sprocket pulsey SP2 arriving ontermi nal 499 from delayline (Figure 2a) to pass through this gate `491. A fter passing thisgate, SP2 setsV the l2() check'ilip-flop 493. This ilip-flop 493 is,therefore, set whenever they seven-stage binary counter 1110i Figure 2b'has counted 120 read-in steps. The set output-of` flip-flop 493'produces a permissive signal to gate 482;' Flip-flop 493'is restoredthroughthe application offeither' the manual start signal o -r theautomaticy application of; the read start signal. f

A-fte'r gate 482 has `been alerted throughthe application of the setoutput signal from' flip-ilop 493, theresthore output from aresettabledelay op RDF/'281r may'pass;jv

through gate 482; and theoper'ation'of this resettable delay ilop'willnow be explained. Every time a sprocket pulse SP arrives from line 104in FigureZa it isi/appliedl to input'terminal 4&0' of resettabledelay'ilop 481 to lset the delay 4ilop 431.' This resettable'delay flop'isay one shot multivibrator which has a delay time of '4-00-micro"fseconds. When' it restores, it produces thefoutput signal which passesthrough gate 482. It will, however, restoreA` only if andwhen 400ymicroseconds have been elapsed since: the arrival of the very' lastsprocket pulse SPL Such circuitsvhave been used in' radarsystemsas'pulsef stretchers.- Atypical such circuit is` disclosed inU.'S.v

Patent No. 2,719,226, issued Septf27, 1955, to Gordon:

et al., iiled June 4, 1951.`

It-fhas beenstated hereinabove that, in general, char-` acters landsprocket pulses arrive at the magnetic'head"' Let us assume now that,foi-'some reason, characters' arid sprocket pulses i arrive at a muchslower speed. This will happen, forV approximately every' 80microseconds.

example,\if the characters on the magnetic tape have one inch of tape.

microseconds would, therefore,fbe' a suicient delay. For

safety 'reasons this delay was, however, doubled to 400 microseconds.

After '400' microseconds'have elapsed since the arrival of the lastsprocket pulse'SP,v the restore output' ofdelay flop YIRDFllSlL passesthrough gate' 43%. This gate'482lr is' open for passage' after the 120count. The vsignal is" 467 of the tape driveip-flop A15;

As soon-asv ilip-ilop 15 "restores,

comes to a stop andl the read-in cycle'is complete.:

The sameI output 'signal'from Flip-Hop "15; whichl ener-- gizes they'brake-"mechanism is 'also applied-as 'a sustained" permission to gate"22 during thetimethat printing shouldj` occur.FV lf` thisfres'toresignalrfrom'ipop 15' coincides* with the `endipaper feed signalf'fromthe paper-feeclcirfV cuits in -Figure 5b, it passes through gate'22"and'opeii' atesfrom thereon as the 'start printcyclesignal as will*bediscussed hereinafter' inf-'connectionwith-'the\explana^tionof-theeprintingfoperations.

the clutch 13: *iside-i energized 'and-the brake mechanism' 14 'isactivated." As' Va result-,rthemotion of the 'tape across theI readinghead Gate 22 performs two functions. `One function which was explainedin the preceding paragraph is to inaugurate a new print cycle whenever aread-in cycle has been completed. The other function is to bring themachine to a standstill, either automatically or at the option of theoperator. In other words, if the machine is to be brought to a stop,this stop occurs at the end of a read cycle. This is effected by aninhibitory signal to gate 22 as a result of which the restore outputsignal from the tape drive flip-flop 15 cannot pass through to becomethe start print cycle signal. The signal which operates as an inhibitionon gate 22 is sent by the stop flip-flop 471 whenever this flip-flop isput into its set state. Figure 4 shows three signals which may set thestop flipop 471. There is, rst, the manual stop signal from the controlboard. This `signal enters the circuits of Figure 4 at the terminal 476,is then differentiated by differentiator 477 and sets delay op 475 for aperiod of one-third of a second. Delay flop 475 operates as a pulsestretcher. Its set output signal lasts, therefore, one-third of a secondand passes through gate 474 to enter the stop tlip-iiop 471 at its setinput terminal 472. If the manual stop switch on the control board isoperated after the restore output signal from tape drive flipop 15 hasbegun to pass through gate 22, the passage of the manual stop signalthrough gate 474 is blocked through the inhibitory effect of the startprint cycle signal on this gate 474, as illustrated in Figure 4. Thisprevents stopping the machine in the middle of a print cycle.

The second signal which may set the stop flip-Hop 471 is a stop signalfrom the tape which cornes from the nonprinting special symbols decoder49 of Figure 3 and enters the circuits of Figure 4 at the terminal 478.The third signal which may have a setting effect on stop flip-flop 471is the print error signal which comes from gate 274 in the printcircuits of Figure 9. The stop ip-flop 471 is restored throughapplication of the manual start signal to its restore input terminal473.

There may be also a temporary inhibition of 20 milliseconds duringmultiline operations. This temporary inhibition will be discussed inthat section of the specication which deals with the multiline circuits.

The paper feed circuits will now be described and integrated into theoperation of the rest of the machine. The paper feed circuits areprimarily used to feed paper, but they also generate signals whichcontrol the operation of circuits not associated with paper feeding. (Itwill be appreciated that this is important in the functioning of such acomplex apparatus.) As an example, paper cannot be fed during a printingcycle and a printing cycle cannot be initiated until an end paper feedsignal has been generated. The paper feed circuits permit two basictypes of feed to occur which may be called normal feed and"fast feed.The normal feed operation will be described followed by a description ofthe fast feed operations. However, before considering the normal feedoperation, an examination will be made of rstly, the conditions when themachine is initially started, and secondly, how some of the signals usedin the paper feed circuits are generated.

As previously described, the normal operating cycle consists ofconcurrent read in and paper feed cycles followed by a print cycle.During this normal cycle, an end paper feed signal is generated by thepaper feed circuits, without which the print cycle cannot be initiatedby gate 22, Figure 4. When the machine is first started, there may be norequirement that paper be initially fed, but an end paper feed signalmust be somehow generated so that a print cycle may commence upon thecompletion of the read in cycle. The end paper feed signal is generatedin the following way. Referring now to Figures 5a and 5b, the manualstart signal (shown at the lower right in Figure 5b), initiated when themachine is firstr started, passes through buffer 354 and triggers adelay op DF 320 which produces a signal on its lower output line(delayed output) ten milliseconds later. This delay flop 320 outputsignal passes through dilferentiator 346 and uninhibited gate 303,setting a flip-flop FF 312 whose output generates the end paper feedsignal, thereby subsequently allowing the first print cycle to takeplace as will hereinafter be described. Thereafter, the end paper feedsignal is generated automatically as the machine performs its operation.It can be seen that although paper may have never been fed, an end paperfeed signal is simulated by the manual start signal when the machine isfirst started.

Having described how the initial end paper feed signal is generated,there will now be described the derivation of certain signals utilizedin the operation of the paper feed system. In particular, these arecertain Iof the fast feed signals which are derived from the programpaper-loop system 386 (Figure 5a) and the paper-feed stop signal derivedfrom the paper-feed commutator 399. Commutator 399 corresponds to thesingle optical flat 42 shown in Figure 1, and paper-loop 380 correspondsto the paper-loop 51 of Figure 1. The source of other signals utilizedin the paper-feed circuits will be described hereinafter. In Figure 5a,it will be observed that the paper-feed commutator 399 and the programpaper-loop drive 385 are mechanically ganged on the shaft 39 which alsodrives the paper feed sprocket 41 shown in Figure 1.

Also connected to shaft 39 are paper-feed brake 38 andv the'paper-feedclutch 37. Clutch 37 and brake 38 in cooperation with a driving motor(not shown) cause shaft 39 to rotate and feed a length of paperdetermined by the time interval between signals appearing on the clutchinput line 373 and the brake input line 374. The paper feed signal online 373 causes the clutch to be engaged thereby starting thepaper-feed, and a subsequent paper stop signal on line 374 causes thebrake to be engaged thereby stopping the paper-feed. The paper feed andpaper stop signals are the mutually exclusive output signals of aflip-flop FF 36, Figure 5b and therefore when one appears the other issuppressed, so that the clutch 37 and brake 38 can never besimultaneously engaged.

The paper feed commutator 399, which performs the function of stoppingpaper feed, consists of three discs, 395, 395', 395". Disc 395 has, in atypical instance, six equally spaced hat surfaces 396 around itscircumference, each at surface corresponding to one sixth of arevolution of shaft 39 which represents a single space paperfeed. Disc395 has three equally spaced flat surfaces and disc 395l has twodiametrically opposed fiat surfaces, corresponding respectively todouble space and triple space paper-feed. It will be understood thatother disc arrangements could be used to provide different paper spacingcombinations. Single, double, or triple space paper-feed is selected byjumpering energy source 393 to plug 398, 398', 398, thus respectivelyenergizing light source 394, 394', or 394". Light sources 394, 394', and394 are oriented to illuminate disc 395, 395 and 395 respectively. Theillumination reflected from a disc passes through converging lens 391and is focused on a photosensitive transducer 392 which converts thevreceived illumination into an electrical signal. This signal appears online 370 and stops the paper feed, as will subsequently be shown. Figure5a illustrates the condition for single space paper-feed, wherein energysource 393 is jumpered to plug 398 thereby energizing light source 394which illuminates disc 395. As disc 395 rotates during paper-feed, oneof the six flat surfaces 396 will assume the proper position to reflectlight into photosensitive transducer 392, which will then generate asignal stopping the paper-feed. It is apparent that six such signalswill be generated from disc 395 for each revolution of shaft 39, Whilethree such signals would be generated from disc 395 for double spacepaper-feed, and two such signals from disc 395 for triple spacepaper-feed.

Thefprogrampaper-loopsystem 386 ge 'r'ate's'control signals that arie`used in the fast-feed circuits.; A ,The fast-feed circuits prevent thepaper-feedrcommutator 399, previously described, from stopping the paperafter a single, double, or triple space feed.v The paper-loop maygenerate control signals vthat initiate or stop a fast-feed operation.For purposes of illustration, the program paper-loop system 38.6,isshownv generating three fast-feed stop signals andorre' kfast-f ed i,start signal. The three stopsignal's'are v designatedfighting IO nel 1,fchannel 2, and fchannel'faj andthe st ar signal is: designatedfast-feed 3'."/" AChannel. 3' supplies't e,y stop sil'g'nal'for afast-feed operationfinitiatedby the fast-feed 3f signal, b'oth ofthes'evsiginals'binggenerated thel paperlo'op system'. Cl'iannefl andchannel l2 supply 15 the stop/signal ,forl a fast-feedoperation,initiatedby fast-feedll or fast-feed 2 signal, these latter"signals, h9w'ever`, 'are not generated `by the paper-loopJ sfyvstm.`fastlfeed I'or fast'feed 2`jsig`n'al, when occ'll'rS, *is initiated'by'the' iirs'tcharac'ter O'faninformation blockette 20 readv from the'Amagnetic tapeduingfa read'g infs cycle., This first character becomesidentified as 'a -fastfeedl or fast-.feed 2 signal when it emerges fromthe/nonprinting c symbolsdecoder 49 (Figure'3), earlierdescribed.lulrri-l Y ingfnow to a closer inspection ofl the'ypr ogram.lzrapehr:. 25loopsystem 386`it'is seen that an`endl'e`ss' paperj-loop 80 looped'around shafts 332 and 39 revolves in synchronisrn withl the paper-feedcommutator and. the paperjfeed sprocket (not jshown), as shaft39'revolv'es'. The paperloop 380`is perforated with holes 381I,.vvhich,togetherl with hole-sensing'brus'hes 333 generate the channels` 1, 2,j3,and fast-feed`3signals through `aconventional contact typesignal'generator 384 whenever a brush sensesY a hole'in the paper-loop.`As shown,theholes'SIare disposed' in discrete channels', orftracks,Completely 35 traversing `the paper-loop` 380, each' channel being as-Asociated with afpartic'ular hole-sensing brush 383 and generating aparticularv fast-feedlsignal.: It Will ybie/hereinafter recognized thatalthoughthe programpaperloop` system generates signals which stop afast-'feed opera-V 40 tion, nevertheless, the precise position.v atwhich the' paper beingjfed is stopped will be controlled by thepaperfeed commutator 399. This condition is necessary tolpreserye thetiming structure of the machine and ytofinsure that uniform line spacingbe maintained. The specific means,

by which'this is accomplished will bensubsequently; deb-nV scribed. yThe program paper-loop systemw performs. essentially two programmingfunctions, Firstly, itremovesY the' burden from'ltheinformation source,.such as a com-, puter, of having to supply signals which bothstart and`5() strop a fast-feed operation. It is only necessary for thefl sourceto initiate a fast-feed, the paper loopcsupplies the stop signal.Secondly, it can both initiate and stop a., fast-feed operation" incases where' the paper' feedingA requirement isv imposed by`condition'smexternal toV the 55 information source. As anexarnple,`.considerV ,the` casev Where apre-printed form is being lledin, `such l,as la tax-form`or a billing form. Each fo'rrn fed by.` thepaperfered isidentical to the preceding andsucceeding forms, andfurther, each form contains discrete'locations'for 60 the entry ofspecific items of information."4 Generalliy,` one form' will besufficient to accommodate allfth'eentrie's for'any given' account, butoccasionally ani'account may require more entries under a specificinformation item l than there is space available. This, ofv course,Irequires that the succeeding form be used to accommodate the*vr excessentries, or overflow, and' these entriesmust' be madepat the properplace on the lformiv Suppose that the information source supplies,`morejentr'ies thanlcan be accommodated by the particularl location onthe forro.l Itis apparent that if no ,steps are taken, the remainder ofythepentr'ies will be printed at the beginningfof the next location, anincorrect position` forsuch `entries.l Certainly,f such afsitnatonicouldfcbe talreninto accounty by programming apprpr'iatesignals infoiliinf'rfr'n'a'fiori"'75y I' fit nu .112i j. :.:::',f source; However,thisl islnndesirable because itrequires the information sourceto-takeginto ,account the extent of particular set of items.` l Anychange in the? fof ,mat would require a re-programming ,of theinformation source.` This is a needlesscomplication of already,vcornplex equipment. This burden can be completelyL removed from theinformation A,source andY transferred to lthe paper-feed system of theprinter. j The paper-loop` system 386m conjunction with thek circuits ofFigureb represent a novel means of accomplishingsucha result. Since thepaper-loop 380 revolves in synchronism lwith the ipaperv feed sprocket(notshown), specific locations onltheV paper-.f4 loop correspond tospecific positions on the `form being fed by the paper-,feed roller. If`a hole islpunchedin `the fast-feed 3y channel of the paper-loopcorresponding to the last entry lineof the particularform location, whenan overflovvrcondition occursfa fast-feed 3 .signalwill be.v generatedwhichvvill initiateha fast-feed operation. ,This will cause thepaperfeed roller to continuouslyV feedrthez. form until a fast-feed stoporder occurs. v This stop'order. isY generated bynahole in the channel?,channeloftheI paper-loop whichis punched at a position corresponding tothe formlocation proper toreceive-the overflow, which, will be on thesucceeding form.y V.In addition, the program paper-loop supplies channelland channel 2 signals which. are stop orders for fast-feed operationsinitiated by, the, infomation source via the fast-feed 1A or `faS'feedA2,-: signals. These latter two signals, when they occur, are aspreviously indicated the first character in` an information blockette,andy can be'cused to signify the beginning ofrya new information item`onrthe above. discussedl forrm. vr Since the arrival time of aninformation blockette bears4 no fixed relationshiprto the positionk ofythe form, somey indexing system must be used to insure that .theinformation is printed at the proper locationfx This function `is lperformed by the paper-loopchannellor| channel 2 stop4 signal, as willnow be shown. When all, the entries to bemade under a given item ofaparticular, accountrhave been entered, space may remainmfor additional,entriesi whichvwill, of course, not be forthcoming. The next. blockettewill initiate a fast-feed operation whichrmust, b e terminated at thebeginning of the next item location onthe Afl'orrn.'` The termination ofthefast-feed isproyided. by alhole in the channel 1 or channel 2 channelofthe paperloop, punched at ay position correspondingto the;properlocation on ,the form. JA channelv Lsignalfwill stop a fast-feed 1loperation and a channel 2.signal willL stop a'fast-feed 2 operation.lTherefore, it Willbe seen that although the initiation of `a fast-feed 1or fastf'feed 2l operation is indeterminate with respect to thevpositionofthe form, the position of Athe lform determines,vr/hen,` thefast-*feed operation will stop rlay-'virtue of theoneto onecorrespondence ofthe formI position to ,the paper- Y loop'380 position,thuswproviding/the required indexing. The fast-feed 1 and fast-feed 2signalsfoccur at the begin7` ningof a read inb cycle,butshould.thefastifeed operation/continue beyond the fread in time, ,theprinting cycle, is inhibited until the feed operation. has terminated...It is convenient to' maintain a le of paper-loops .thatA are punched toaccommodate the formats of `thevarious forms used. These-paper-loops canbe. use d repeatedly, thus` simplifying'tle programming of" theinformation source.y y, l y Having" now described the conditions whenlthemachne.

is* initially started, and furtherhhaying described the` operation ofthepaper-feed ycorrrmutator and the program paper-loop system togetherwith signals'generated there-v frompwe will turn lto a detaiedexamination of the.V circuits of Figure 5b.` In orden; we vvill'considerntheg each `in'itiated'and hon/ y they cooperate 4vvithvothersectors of thmacliinetoaffect'the'oyer-all operation.'y l I V`Thelfnormal feed. operation' isfinitiated,v at..tlxelvfelitl-A The readstart signal passes through buier 352 and sets the flip-flop 36 theoutput of which via line 373 causes the paper-drive clutch 37 to beengaged. This in turn causes the paper-feed commutator 399 (Fig. a) torotate and ultimately generate a signal on line 370 in the mannerpreviously explained. The signal on line 370 passes through gate 301(Figure 5b) which is uninhibited in the absence of a fast-feed signaland restores the flip-flop 36, the restored output of whichsimultaneously takes three separate paths. First, the restored output ofthe dip-flop 36 via line 374 causes the paper-drive brake 38 to beengaged, thus stopping the paper-feed. Simultaneously, the clutch 37 isdisengaged as hereinbefore explained. Second, the restored output of theip-op 36 passes through buffer 365 and inhibits gate 304, therebypreventing a fast-feed 3 operation from being initiated by the programpaper-loop system. Third, the restored output of the ip-op 36 isdifferentiated in differentiator 340 and triggers delay ilop 320 throughbuffer 353. The trigger output of the delay op 320 inhibits gate 302 forten milliseconds in order to provide for electrical stabilization of thepaper-drive clutch system before permitting a fast-feed signal, if onewere now received, to set flip-flop 36 and re-engage the paperdriveclutch 37. The primary purpose of the delay op 320 is, however, to allowa ten millisecond delay before starting a print cycle. This is necessaryto insure mechanical stabilization of the paper and thereby preventmisalignment of the print, which would occur if printing were doneduring this time. At the end of the ten milliseconds delay produced bythe delay flop 320, the trigger output disappears and the delay outputappears. This delayed output passes through dilferentiator 346 to thegate 303, which is uninhibited in the absence of a fastfeed signal. Theoutput of the gate 303 sets a ip-flop 312, thereby generating the end ofpaper feed signal. This signal appears at gate 22 of Figure 4, and itspresence is a pre-requisite to the initiation of a print cycle. Thefunction of this signal is more fully explained in connection with thedescription of Figure 4. With the generation of the end of paper feedsignal the normal feed cycle is completed. Assuming that a normal printcycle follows, the code generator, shown in Figure 8, as subsequentlydescribed generates an "end of print cycle signal at the termination ofthe printing operation. This signal passes through buffer 367 andrestores the flip-hop 312, thus terminating the end of paper feedsignal. A read start signal is generated by the print circuit gate 275,Figure 9, three milliseconds after the end of print cycle signal and thehereinabove described normal feed cycle is reinitiated.

The fast-feed operations are of two kinds, namely those initiated by asignal from the information source, such as a magnetic tape, and thoseinitiated by the program paper-loop system 386. Operations of the rsttype are illustrated by the fast-feed 1 and fast-feed 2 circuits, whilethose of the second type are illustrated by the fast-feed 3 circuit.Both types are terminated by signals from the paper-loop. Although thefast-feed 1 or fast-feed 2 operation will always be initiated by thefirst character of an information blockette (in accordance with theembodiment described), the termination of the operation is contro.led bychannel 1 or channel 2 respectively of the paper-loop 380 which willgenerally be holepunched at different places. It will be understood thatadditional fast-feed operations may be obtained by suitable modicationof the paper-loop system and by duplication of the circuits of Figure 5bhereinafter described.

In order to insure that the routine set up on the paperloop 380 will notinterfere with the requirements established by the information source, afast-feed order is established whereby a fast-feed 1 or fast-feed 2operation will always take precedence over a fast-feed 3 operation. Themanner in .which .this is accomplished will be de'- 18 scribedinconnection with the fast-feed 1 operation described hereinafter.

The rst SP1 signal (delayed sprocket pulse) obtained from delay line 105of Figure 2a gates the fast-feed 1 or fast-feed 2 signal through thenon-printing special symbols decoder 49 as previously described inconnection with Figure 3. Since the fast-feed 1 or fast-feed 2 signalwas the rst character of an information blockette, the address linecounter, also previously described in connection with Figure 2b, rwas inits cleared condition and had energized address line 0 just prior to thegeneration of the fast-feed 1 or fast-feed 2 signal. The address line 0signal conditions the gates 305 and 306 so that the fastfeed 1 orfast-feed 2 signal subsequently arriving at its respective gate inputwill be permitted to pass through. For purposes of illustration, assumethat a fast-feed 1 signal arrives at the input of gate 305. This signalwill pass through gate 305 and set flip-flop FF 313.

It will also simultaneously pass toline 371 through buffers 355 and 369,and to restore the Hip-flopY 315 through buffer 357. If a fast-feed 3signal had previously been generated by the paper-loop system 386, thefastfeed 3 signal would have passed through gate 304 and differentiator343, and thus set flip-hop 315. The set output of flip-flop 315,however, would not have passed through gate 306 since neither theaddress line 1 nor the second delayed sprocket pulse SP1 have as yetbeen generated, these latter two signals being associated with thesecond character in the information blockette. When these signals doappear at gate 306 no fast-feed 3 operation, if set up, could beinitiated because the fast-feed 1 signal has restored flip-flop 315. Therestored output of flip-flop 315 passes through buffer 360 to line 372and thence through diiferentiator 345 to the restore input of Hip-flop311, which is already in the restored condition. Simultaneous with therestoring of flip-hop 315 the fastfeed 1 signal on line 371 triggersdelay flop 321 and initiates a microsecond pulse from pulse stretcher330. The 100 microsecond pulse passes through buffer 364 and inhibitsgate 304, thus preventing any subsequent fastfeed 3 signal from againsetting flip-flop 315. Delay op 321 produces a delayed output50microseconds after being triggered by the fast-feed 1 signal on line371. This delayed output passes through differentiator 344 settingllip-op 311 and restoring ilip-op 312, if it had been set, throughbulfer 368. The set output from ilip-op 311 passes through buffer 366 togate 304, maintaining the inhibition on gate 304 after the 100microsecond pulse from pulse stretcher 330 disappears. Thus, it can beseen that a fast-feed 1 signal takes precedence over a fastfeed 3 signalby restoring flip-flop 315 prior to the opening of gate 306, and byinhibiting gate 304 thereby preventing any subsequent fast-feed 3 signalfrom again setting flip-flop 315. As has been shown, gate 304 isinhibited during the entire fast-feed 1 operation by the combinedeffects of pulse stretcher 330 and flip-flop 311. Pulse stretcher 330 isnecesary to maintain the inhibition on gate 304 until the set output offlip-flop 311 appears, this output being delayed by delay op 321. Thedelay introduced by delay flop 321 is necessary to insure that thefast-feed 1 signal on line 371 does not arrive at the set input offlip-flop 311 until after the restored output from Hip-flop 315 hasarrived at the restore input of flipop 311; the restored output offlip-flop 315 also having been generated by the fast-feed 1 signal.

The set output from Hip-flop 311 in addition to inhibiting gate 304inhibits gates 301 and 303, and sets ip-op 36 through gate 302,differentiator 341, and buffer 351. The set output of flip-flop 36causes the clutch 37 to be energized and the brake 38 to be de-'energized to start paper feed. The inhibition on gate 301 prevents thesignal generated by` commutator 399, and appearing on line 370, fromrestoring flip-flop 36. Thus, paper continues to be fed until thechannel 1 signal is generated by the program paper loop 380. This signal

